Pro R Lower A-Arm & Knuckle Kit

The PRO R Lower A-Arm and Knuckle Kit is the ultimate front suspension upgrade for Polaris Pro R and Turbo R owners who demand race-level durability, precision steering, and long-term reliability. Designed and manufactured by Lone Star Racing, this kit replaces the factory lower A-arms and knuckles with a fully reinforced, double-shear suspension system built to survive extreme racing and aggressive off-road abuse.

Constructed from heavy-duty 4130 chromoly steel and TIG welded for maximum strength, these lower A-arms eliminate factory weak points while retaining OEM hubs, brakes, and chassis mounting hardware for a clean, bolt-on installation.

At the heart of this system is a vertical 1″ FK uniball lower joint, replacing the factory ball joint entirely. This setup dramatically increases strength, articulation, and service life. A 3/4″ FK uniball shock mount further improves durability at another high-stress location.

The included billet knuckles feature a relocated tie rod mounting position, significantly improving steering geometry and reducing harsh feedback through the wheel. Every critical mounting point is now double shear, providing massive strength gains over stock components.

This kit is Baja proven, having survived 1,300 brutal race miles under Branden Sims with zero uniball play—a true testament to its durability and engineering.

🛠️ Key Features & Benefits

• Heavy-duty 4130 chromoly lower A-arms
• TIG welded for maximum strength
• Vertical 1″ FK uniball lower joint (ball joint replacement)
• 3/4″ FK uniball shock mount
• Fully double-shear knuckle design
• Improved steering geometry
• Reduced steering feedback
• Retains factory hubs, brakes, and chassis hardware
• Works with any tie rod kit using a 3/4″ heim
• Misalignment spacers included
• Baja race tested & proven

⚠️ REQUIRED COMPONENT

🚨 This kit REQUIRES Lone Star Racing Adjustable Upper Control Arms

Compatible upper arms:
Polaris PRO R / Turbo R HD Upper A-Arms – Lone Star Racing

This system is engineered as a complete suspension package and will not function properly with stock upper A-arms.

🔧 Tie Rod Compatibility

• Works with any tie rod kit using a 3/4″ heim joint
• Misalignment spacers included for double-shear mounting
• Optional Shock Therapy Tie Rod Kit available
  ➕ Add for $849.95

🚙 Vehicle Fitment

• Polaris RZR Pro R
• Polaris RZR Turbo R

📦 What’s Included

• (2) 4130 chromoly lower A-arms
• (2) Double-shear billet knuckles
• FK uniballs (pre-installed)
• Required misalignment spacers
• Installation hardware (where applicable)

🏁 Race-Proven Confidence

If you’re pushing your Pro R at race pace, blasting through desert whoops, or hammering rocky terrain, the factory front suspension simply isn’t enough. The PRO R Lower A-Arm and Knuckle Kit delivers next-level strength, precision steering, and bulletproof reliability—engineered for racers, tested in Baja, and trusted by professionals.